Custom Battery Packs? INTERESTED?

[torqueboards]

I've been thinking of a set standard on battery packs and believe it's finally time to create a simple standard on what kind of battery packs work perfectly well for our DIY Electric Skateboards.

I'm been looking into moving into 18650 Lithium NCM cells and/or 26650 LiFePO4 cells with built in charging ports.

My Reasons For Choosing Completely Custom Battery Packs
- completely custom build battery packs -- under 1" (Ex 8/9ah) or 1.5" - 1.5" if you want more capacity/longer distance Ex. 11ah
- longer life cycles
- built in charging ports
- option for cheaper battery chargers (use of multiple packs) (ex. work/home)
- safer battery packs
- safer charging - ability to leave charger alone no need to watch or monitor your charger (aka lipo)
- battery led indicator *save additional cost built-in
- built in on/off switch *save additional cost built-in

A low profile metal enclosure is on my to do list as well.

I'll actually create a post on this as it's something I've been looking into lately.

COSTS!!!
Factor in the costs for a nice lipo battery pack other than 6S --> 8S/10S/12S are hefty in cost and lack the other great features. $100-$160.

A HobbyKing 350W Power Supply + iCharger 208B = $160-$180

Easily a $300 battery pack for LIPO!

We could very easily have a $300-$450 battery pack that would have 2-5 times the life cycle as a standard HK Lipo battery.

Replacing our batteries every year or every other year isn't ideal. It ends up making our boards cost way more then they should.

What are your suggestions and your ideas on a custom battery pack that is most ideal?

Enclosure Questions

Do you prefer an aluminum one piece enclosure that goes across the entire bottom deck?

Do you prefer two aluminum enclosures to keep the flex within the center of the deck?

Define your most ideal enclosure for your battery pack + electronics?

 

[drmacgyver]

100% behind your battery idea! Definitely at least 8ah, especially bc from what I've read on here pneumatics get less range. My HK150a esc only takes up to 6s, so not having to get a new esc would be nice.

As for enclosures, definitely sold on aluminum, again from what I've read on here (help dissipate heat and serve as a safe box for batteries). 1" in height would be perfect. Currently, I've got 2x3s8000s, so the minimum width of my box has to be 7" to leave room for wires, which will run between the two (not at all an ideal width). I'd imagine your battery will be much narrower than 7" though.

I'm stuck at the same fork in the road, regarding the placement. On one hand, I love Boosted's setup, with the wires concealed under the grip tape. But I'm not sure if there's a significant advantage to a split setup that would merit the work to make it. My board is stiff, and I'm planning on future decks to be too, so that's not a factor for me.

 

[Hummina Shadeeba]

Ive been looking to do the same. Make a 18650 pack (preferably no soldering), or possibly the smaller ######. Why do u like the NCM lithium? The li-ion will hit 20c and i hear thats good enough. I read places like hk over state their c rating on the lipo. I forget what amps people get to but do you think 20c is adequate to get the amps wanted and not mess up the batteries?

Adding the onboard charging port seems simple to make too.
Ive come to hate and still suck at soldering and was looking into other ways to connect.
Ill probably solder and then Id like to sink the pack in my board w epoxy n maybe something else like fiberglass r carbon but think the expansion n contraction would maybe ruin it or lack of heat disipation. But maybe spot gluing? How bout the esc n receiver as well? Would it be too much vibration?

 

[drmacgyver]

Shadeeba: I've seen a video that showed how to assemble lifepo4 cells that had screw tops and connected to each other with either copper or steel brackets. If I can find that video I'll link it. I'd imagine soldering would be a more reliable method though.

I think 8 of those 3v blue lifepo4 cells would make for a nice size/power pack (2 rows of 4). And I think they're 10ah too, which is awesome.

 

[torqueboards]

I've been looking into a 7S 8800mah pack and a 13S 8800mah pack. Still debating and looking into if I want LiNCM packs or LiFePO4. LiFePO4 has a much larger life cycle rating than LiNCM - Although, heavier and bigger.

I was planning on about 7" width and perhaps 12" or longer and 1" height is what I would prefer.

13S 8800mah will actually get you much further than 7S 8800mah because of the Watt Hours. However, I have yet to figure out the actual run time for both.

We aren't using Lipo batteries so they are much bigger in size or slightly bigger.

I also prefer stiffer decks as I go downhill and uphill more often. I do need them to flex a little as I tend to ride down slight curbs. Too stiff and it might put stress on components. I do like enertion's setup with the wires underneath as trying to put them over the board for a kit is a bit too much unless you know how and have the tools.

I'm thinking of going with an aluminum enclosure that can be easily removed. I'm also trying to think of how it can be easily opened as well even though with these packs it probably doesn't matter a whole lot. What do you guys think? For some reason, I still like the option of easily opening my enclosure regardless if I ever use it or not.

So far from the looks of it. 7S 8800mah will cost about $200-$220 and a 13S perhaps about $300-$350 in LiNCM. Haven't fully checked on LiFePO4.

My pack ratings are about 40A Cont and 80-100A Peak. With a 13S pack we won't nearly hit those amp ratings and they would actually be way less. Perhaps on the 7S it may be around those ratings.

I choose LiNCM for lighter weight and cheaper cost. I'm still debating as the LiFePo4 life cycle seems to be much more. Just need to decide if the trade off is worth it aka bigger packs + heavier weight.

ESC + Receiver shouold be fine. Velcro adhesive from HobbyKing seems to work real well. They can take the vibration. I would wrap my battery around a thin piece of foam although my current lipo's aren't and it's fine.

 

[torqueboards]

I think 8 of those 3v blue lifepo4 cells would make for a nice size/power pack (2 rows of 4). And I think they're 10ah too, which is awesome.

That size would be just cells alone and not with a BMS and charging ports. Would be very similar to the lipo setup and charging that we currently have. I prefer having it all built in already makes it easier.

 

[Hummina Shadeeba]

Shadeeba: I've seen a video that showed how to assemble lifepo4 cells that had screw tops and connected to each other with either copper or steel brackets. If I can find that video I'll link it. I'd imagine soldering would be a more reliable method though.

I think 8 of those 3v blue lifepo4 cells would make for a nice size/power pack (2 rows of 4). And I think they're 10ah too, which is awesome.

I can't find the pic. One of the coolest boards I've seen. On wacky boards .com or sounded like that. It was an aluminum deck with 2 or 4 red batteries which looked like they simply bolted at the terminals. Like the visible-board. Probably protected enough and a safer chemisty than lipo and ok exposed to rocks flying. Ill be looking for those connectors and how they do. I've seen pressurized with foam or something non-solder connections but not for sale to build something as small as 8ah. Loose cells that screwed on w some electrolyte jell at the connection if need be.. Still sounds very convenient. And cool looking.



Translucent DIY batteries might be cooler

 

[bandaro]

18650's are good cells, so while I personally wouldn't buy one from you, I would make a similar thing myself. Partly to save the 20 bucks, partly for enjoyment, partly because I feel a builder needs to know how everything in the board fits together and works. But I have a strong design and manufacturing background, so can do it all myself anyway.

I do however really like what you are doing in the scene, making DIY boards an option for the masses. I lack programming, but if you need any help regarding the design/manufacture of components let me know.

 

[onloop]

@torque they say great minds think a like

I too have been thinking about higher voltage for some time now, even more lately since vedder came on the scene with his high voltage ESC.

I have also been spending more time reading about electric bikes, the DIY E-bike scene has a lot more minds and several years head start on the DIY eboard scene... I guarantee you won't find many people building e bikes with 6S batteries. In fact even 8s or 10s is too low for most.... & there is a good reason, higher voltage is more efficient.

Obviously you can build higher voltage batteries using LIPO... but it gets problematic... Lipo pouches are more difficult to arrange when you are dealing with the small area under a skateboard deck. I must also mention more volatile chemistry.

So whats the smallest high quality battery available... looks like 18650 is the winner! at only 18mm diameter its VERY SLIM... However it needs to be used in a system thats not going to suck it too hard...Or you need to build a very large pack so it can supply the appropriate power output... but we only have the size of a skateboard to work with.

The li-ion will hit 20c and i hear thats good enough.

What cells are you referring to? Are you talking 18650 type? I think the Sony VTC5 are 12C which equates to MAX 30A cont discharge.


So i have spent some time thinking really hard about how to design the best electric skateboard components housing possible to hold the large number of cells required to deliver the power we need.

I love aluminium, it is relatively low cost, low weight & also fairly easy to work with & i think it looks great >>>

The only problem with aluminium is it you need to use what is already available, or make your own design by extruding from a mold, so to make the perfect housing to hold 18650 cells you have some expensive setup costs before you get your final product.

Also aluminium can interfere with radio signals, so for you guys with Wii receivers that would have to be housed in something else because there is no antenna to mount externally....


I personally think separate box for battery & esc is better for several reasons, for example having them separate is better for people who want to use a slightly flexi board as the flexi bit is in the middle where you don't have stiff aluminium....

However when you start to size up your 18650 cells into a format that can offer ample Wh (enough for 1.5 to 2hrs ride time) you realise that the size of the battery is fairly large, especially when your primary objective is SUPER-SLIM... which is what i want.

If you don't care about component housing thickness you have many more options.....

So you get to a point, due to battery size, where there is no point having them separate, because the gap would be about 1 inch! so no benefit.

So for me i am focusing on one single components housing......

My reasoning is, that most people do not want really flexible decks... mostly because they are not great for handling when travelling at high speeds of 45km/h plus

So this is the concept i'm working on at the moment, its a constructed housing made from a composite of carbon fibre, GR10 plate & aluminium.... super lightweight, very strong, no radio interference, only 24mm thick, & looks frocking sexy!

[youtube]HdZmRjFfWuU[/youtube]

I have taken inspiration from multicopter chassis.

I am also developing a special anti-vibration flexible mounting system that will allow the, mostly rigid housing, to be fitted to boards that have a bit of flex... However if you have a really flexiboard you will need a smaller battery and a split housing design.

 

[drmacgyver]

I can't find the pic. One of the coolest boards I've seen. On wacky boards .com or sounded like that. It was an aluminum deck with 2 or 4 red batteries which looked like they simply bolted at the terminals.

http://endless-sphere.com/forums/viewtopic.php?f=35&t=37230&start=75
I think this is the one. Papo2110's board.

 

[voodoojar]

I've been making some packs with these http://www.amazon.com/Panasonic-NCR18650B-Rechargeable-Battery-Green-quantity/dp/B00CB8PGOE

7s2p 6800mah with bms on/off switch and easy charge with the charger is $160
8s2p 6800mah with bms on/off switch and easy charge with the charger is $190

 

[Silenthunter]

Guys,

I have been using 18650 for over a year on 6S, 7S, 8S, 9S set ups for longboards, gopeds esr 750's and mountain boards. It works flawlessly, the more cells in parallel the better (C rating is more than enough). I even tested with used fake Chinese cells and the result was outstanding. I cut on water jet 1/8" aluminium plate and placed some aluminium stand off. Super light and slim. My boards is around 12 pounds and I get 15 miles on flats.

The Panasonic 18650 type B are the best cells but way to expensive. Tesla proved that this is the best cell available on the market.

I saw mentioned above 13S pack...what ESC are you using for that battery? I am looking for a reliable 10S ESC for mountain board application. So far Mamba XL2 is only one 8S esc that proved to work flawlessly for daily commute for over 2 mounts with the right gearing.

 

[torqueboards]

@onloop -- Ebike's are awesome. I've been wanting to build one but no time/space and wouldn't use it as much. Another big rabbit hole to go down. Can't fit the bike as easily on a commuter train and/or at work either.

From what it looks like 33-36" boards would be a bit too small for a thinner and larger pack. 38" - 42" boards similar to boosted/evolve would need to be used to allow for the additional space for the battery packs.

18650 are nice.. Question is supposedly 18650 LiNCM are about 800-1000 life cycles and 18650 LiFePO4 is about 2000-3000 cycles. I could be wrong haven't done additional research on it just yet.

I'm opting for the LiFePO4. If your spending $300-400 on a pack. I'd rather have the longer cycle pack.

That's also a major issue if we want 8ah to 11ah and underneath 1" in height. We need to use all space available. Having a 2 part enclosure makes it a bit more difficult.

I also agree with the flexible decks. I climb hills and go down steep hills with potholes in the way. I'm not really interested in a flexible deck. Also flex decks are mainly used for people going around 20mph and pot holes aren't as existant. If I didn't have to deal with potholes. I probably would think otherwise but for commuters I would prefer a sturdy deck. I also want the added space.

@voodoojar.

Those are some pretty great prices. I think something around 8-10ah would be a bit better for longer rides. What do you expect those 6.8ah packs to achieve in miles? What are the cont amp and peak amp for the pack?

 

[drmacgyver]

Silenthunter, so awesome to hear about your success with those! I remember your board when you posted it. I'm assuming the more relaxed housing is because those aren't as sensitive as lipos? Without knowing a whole lot about either, I guess my vote is for lifepo4 just because of it's longer life span. 36" is my ideal size for a board, but I want a double drop anyways which are 38" and cheap. On my board there's 20" of space (with 1/2" space away from motor and 1.5" back from the front trucks).

As far as pack cells, I realized I would need at least an 8s to meet the voltage of what my 6s is now, which would mean I'd need a new esc for 8s anyways, right?

Also Torque, is there a reason for the odd number of cells, instead of 8s and 12s?

 

[torqueboards]

@Silenthunter - For the 13S, I plan on using Vedder ESC once it's available.

@Drmacgyver - Some 18650's are the same voltage as lipos and are 4.2v max and 3.7v nominal. I plan on using similar cells with 3.7v nominal. Voltage should be equal if you are referring to LiFePO4 you might be right. I haven't done as much research with LiFePO4.

I plan on switching to LiFePO4 for the added benefit of increased life cycles as well. It only makes sense hopefully it doesn't affect the size and weight as much but it perhaps might.

I plan on using my new packs with either the 8S 120A Dual ESCs and/or Vedder's ESC once it's available.

The reason for the odd cells 7S/13S is what is readily available with my supplier which would keep costs considerably lower and quicker to produce. 7S should be fine for single or dual boards looking to go under 20mph. I've been using 6S and I think I've outgrown it and enjoy using my 8S packs but they are considerably much more expensive than my 6S packs as well as since the life span is not as long as I would like. I prefer to use a custom built pack if I'm spending the money anyhow. Not sure how many miles most people have traveled with their board just yet. 8S allows me to go up hills much faster.

 

[Silenthunter]

I emailed him regarding price and availability and so far no answer...

I use my boards daily for @ 30 plus miles and I would love to put his ESC to the test. So far Mamba Xl2 does an amazing job with 11T and 64T gearing. I wish CC creates an affordable 10S esc soon like Mamba Xl3 or something... They have their 160H hydra but it is over $250...I am sure this ESC would work awesome with 10S-12S.

 

[drmacgyver]

I think the minimum height we'd be able to get with lifepo4 is right under 2". The holders for the lifepo4 headways are 40mm x 80mm and the cells themselves are 138mm x 38mm. The 18650's are really small though. I guess the way I see it is my enclosure now is 2.5", so getting down to 2" is still an improvement. Add to that a better battery and it's a win-win. It's still not close to ideal, which I know will irk me.

As far as speed is concerned, we should factor in the increased speed from the pneumatics for those of us that will be using those. While having extra voltage would be nice too, I've been happy with 6s (1:3 on 83mms). I think the pneumatics will give me that extra speed without having to up the voltage. The only thing I'd like are more AH's, which the lifepo4's definitely offer.

There's other factors to consider, but basically it seems we're talking about:
A slimmer (prettier?) product for a shorter time -vs- a bulkier (uglier?) product for a longer time.

I'm not sure if we'll ever reach a definitive answer, but I'm interested to hear what more people think about "size vs life span".

 

[voodoojar]

Torque, I've been working on a super light board using the 18650 packs and they get about 7 miles on a charge.

The pack that I use in the boards I'm currently selling are 26650 4600mah cells. The 7s2p 9200 mah pack of those are getting about 12 miles on a charge. These are $140

I bought a box of 26650 6000 mah cells to try to make a 12000 mah pack but haven't had time, I'm also dubious of the 6000mah claim.

 

[torqueboards]

@Silenthunter - Yeah, we are actually waiting to do test units and will do a bigger batch once we get closer.

Wow! 30 miles a day! lol Are you swapping packs? 30 miles is a ton.

Enclosure
I also think a one big enclosure is still doable but would take some work. An enclosure similar to Yuneec E-Go would be ideal. Perhaps 1/2" or 1/3" Rubber above the actual enclosure would allow it to flex more. Of course an enclosure would have to be injection molded and maybe something like Glass filled Nylon would work well. We would still be able to get a bit of flex and use 6/7ply boards.

@Voodoo

I'm interested in the 7s2p 9200mah pack. Do you have any in stock? What's cont amp and peak amp?
What else do you have in stock?

7 miles isn't too bad.

 

[dirkdiggler]

I think you'll still find that Lipo packs are the best option. I spend some time over on the ebike forum and most of them are still using Lipo packs or want to switch over. You just can't beat their pricing. You can get 12s 5000mah packs for around $75. Compare that to $300 to $400 for other similar Li chemistry packs. The bikers use higher voltage because of a few reasons. Most ebike controllers are rated at 30amps max. You reduce amps by increasing voltage. Also most of them are trying to increase speeds or get over a certain speed. As you know higher volts equals higher rpm and thus higher speeds. Eboards might benefit from 8s, but not much from running 12s. I've never found that I need to go faster. I've gone the other way though. Lowered the gearing to climb hills faster and make it easier on starting.
Ease of use is another thing, but not worth the extra costs. If you want higher voltage use the Lipo in series. You can get two 5000mah 4s hard case packs for $25 each - that's cheaper than one 6s pack. Plus you keep saying a charger is over $150. You don't need a 150w charger if you charge two packs in parallel. The cheapos will do just fine.
You also will be dealing with larger size and heavier weight with other chemistries. Seems like a step backwards. Again bikes can get away with this, but on a small board you don't have the room. C rating is another factor. Most of these other packs aren't able to drain very quickly. As soon as Rc goes to something else it'll be time to change. I do think the Multistar batteries look interesting and might be great for boards. I've seen a few bikes using them. They have some 16000mah packs. Stinks to get a bad cell on something like that.
In regards to bad cells. It does stink to have to replace batteries every once in awhile, but I had a gas powered skateboard before, and I spent much more on gas. I have batteries that are over two years old still.
I do wish that there would be some more communication between the forums. You are right that they have a few years on us with this stuff. As a boarder turned biker I'm frustrated with ebike controllers. They are massive compared to what boards use. It would be awesome to have an RC controller on a bike, but there are issues that haven't been addressed by the manufacturers. The great thing about RC stuff is the companys make so much product it brings the costs down and they are obviously making things as small as possible.

 

[voodoojar]

Torque I have a big shipment coming in November 9. I'll have to check amps from the bms sheet for these new packs I think 20 45 but I'm not positive.

 

[onloop]

Are there any BLDC motors that can handle above 10S?

Even though the VEDDER ESC can handle 13S, it might not actually be useable due to motor voltage limits.

 

[Silenthunter]

Dirkdiggler,

A lot of people on the bike forum are using CC Edge 160 H esc and it tuns to be working well for years. The only downsize is the 50V limit but it size, weight and ease of installation are great advantages...

 

[dirkdiggler]

No, very few bikes use RC parts. There are only a handful of RC builds that are posted, compared to thousands of hub or Bafang mid-drive bikes. They are much more difficult to make due to their custom nature as opposed to just slapping a wheel/throttle on your bike. Even those few that do use the CC Esc have had many issues due to the lack of current control. The RC ESCs don't last very long on bikes and given the Castle ESC is over $200 not many people want to even try. One spike of current and there it goes. Standard ebike controllers are around $50 for a 48v 1000w controller. The other issue with RC escs are the lack of hall sensors which are more important on bikes.
One of the reasons I think Vedder should work on an ESC for bikes while doing the board. The consumer base is so much higher for bikes. I know it might be fun to do, but sometimes you need to make a living.
I actually posted the question on the bike forum why people aren't using the RC ESCs due to my lack of understanding on the electronics side of things. There is only one poster who likes RC gear and he is using Astro motors on super high end builds (Recumpence - who also did a sweet eboard on here). Crazy that the ebike controllers are 12x6x3 inches and do basically the same thing as a 2x2x1 RC esc.
Sorry, I know this thread is about batteries. :wink:

 

[Silenthunter]

Agreed, but Recumpence is the one that used CC Hydra 160H for 5 years and no issues...and there are many others with various projects. If you set it right it will work. I used 18650 with mamba xl2 and one of them burned because this cheap ntm 50-60 prop motor wire came apart while the other motor and esc was pushing hard. That is the reason why it failed. So if you secure battery,esc and motor wires well it should work well.